[meteorite-list] CAI and chondrules

From: Dark Matter <freequarks_at_meteoritecentral.com>
Date: Thu, 1 Oct 2009 07:49:04 -0600
Message-ID: <822da19a0910010649j6ba9243eu26974abb5ed207ed_at_mail.gmail.com>

Hi All,

I think Jeff's answer was definitive in a boomerang way.

But wait there's more:

http://geosci.uchicago.edu/~grossman/MSD05.pdf

I studied this and other articles looking for the same answers as
those in the initial post.

I'm still looking.

The best I can do in my talks is to quote Don Brownlee when he penned
the following in a 2007 Stardust news update:

"One of the most remarkable particles found in the Stardust collection
is a particle named after the Inca Sun God Inti. Inti is collection of
rock fragments that are all related in mineralogical, isotopic and
chemical composition to rare components in meteorites called "Calcium
Aluminum Inclusions" or CAI's for short. CAI's are the oldest
materials that formed in the solar system and they contain a
remarkable set of minerals that form at extremely high temperature. In
addition to these same minerals, Inti also has tiny inclusions that
may have been the first generation of solids to condense from hot gas
in the early solar system. These include compounds of titanium,
vanadium and nitrogen (TiN and VN) as well as tiny nuggets of
platinum, osmium, ruthenium, tungsten and molybdenum. In certain
chemical environments and at high enough temperature in the early
solar system these exotic materials were the only solid materials that
could survive without being vaporized."

http://stardust.jpl.nasa.gov/news/news113.html

Finally, I have some pics of a rather large CAI in my Accretion Desk article at:

http://www.meteorite-times.com/Back_Links/2008/march/Accretion_Desk.htm

Best,

Martin





On Thu, Oct 1, 2009 at 1:55 AM, MEM <mstreman53 at yahoo.com> wrote:
> I've my own collection of ideas as to how chondrules developed but will save them for later. ?As to CAIs and their presence in carbonaceous meteorites. ?A list member and I had this discussion some time ago and the answer may lie in a process in the "T-Tauri" stage of stellar evolution.
>
> When the T-Tauri protostar goes thermonuclear it loses a mass through a high solar wind output which sweeps a lot of the remaining unaccreted debris from the inner solar system--we believe. ?This is the foundation for our ability to develop isotopic curves of regions based on distance from the sun and explains the rocky inner planets and the gas giants much further out in the solar system. ?This probably is a player in chondrule formation. CAIs are dated to about 2 million years older.
>
> Prior to the hydrogen fuel-burning stage, there was an ongoing fission process which is the likely source for the short-lived isotopes such as 26Al. While I can't lay my hands on the link, I recall some diagrams of a particular phase of T-Tauri accretion where the dynamics were such that even though the solar disk was being spun into a flat, thin, rotating disk, the poles of the proto-sun were ejecting major mega streams of lighter, probably charged particles-- mainly such as calcium, aluminum, carbon, helium, etc. The particle streams resembled fountains spraying very high speed particles many many AUs up and out of the plane of the ecliptic into two giant hemispheres.
>
> If true, this tends to explain the Ort cloud formation and how CAIs were available for inclusion in cometary-like carbonaceous meteorites along with younger chondrules. It explains how CAIs predate the sun's fusion stage and how they were able to skip the mega solar winds generated when the sun kicked over to fusion from fission. Comets forming inside the Ort Cloud but outside the ecliptical plane my be devoid of chondrules (possible example: Tagish Lake)
>
> 1) supernova
> A super nova is theorized to be the catalyst for compressing enough dust close enough for gravity to take over and condense the early initial solar disk getting things spinning into a disk.
>> 2) few time later CAI formation
> Yes but a long time later, possibly explained under the T-Tauri pre-fusion stage during the collapse of the solar disk.
> 3) at the same time collapse of nebula
> Yes but probably well after the accretion stage was under way.
> 4) 2My later condrule formation.
> Yes again
>> 5) at the same time proto-sun and proto-planetary formation
> Probably in connection with the fusion to fusion change-over and during the interval before mega-solar wind swept out the lighter elements from the inner solar system and stopped chondrule formation.
>> 6) ...
> There were probably at least 6 additional Mars sized planets else planetary centers of accretion and some theorize 30 or more. One was accounted for by our moons formation, another knocked Uranus on its side one or more contributed to the asteroid belt. Someplace in the sequence comets formed outside the mainstream goings on in the solar disk/system it self.
>
> Elton
>
> --- On Wed, 9/30/09, Francesco Moser <cojack at tiscali.it> wrote:
>
>> From: Francesco Moser <cojack at tiscali.it>
>> Subject: [meteorite-list] CAI and chondrules
>> To: "ZZ ML Meteorite-List" <meteorite-list at meteoritecentral.com>
>> Date: Wednesday, September 30, 2009, 5:37 PM
>> Hello!
>> I take a look on wikipedia about CAI and chondrules, but I
>> have still some doubt.
>>
>> http://en.wikipedia.org/wiki/Calcium-aluminium-rich_inclusion
>> http://en.wikipedia.org/wiki/Chondrule
>>
>> What prompted the formation of CAI? and what's caused the
>> formation of chondurles???
>> The supernova gave the energy for the formation of CAI and
>> for the collapse of the solar nebula?
>> Some other energy source, still unknow, 2 million years
>> later molten the material which formed the chondrules? But
>> wich type of energy source?
>>
>> Is correct this time line?
>>
>> 1) supernova
>> 2) few time later CAI formation
>> 3) at the same time collapse of nebula
>> 4) 2My later condrule formation
>> 5) at the same time proto-sun and proto-planetary
>> formation
>> 6) ...
>>
>> Thanks a lot!
>>
>> Best regards!
>>
>> Francesco Moser
>> IMCA #1510
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Received on Thu 01 Oct 2009 09:49:04 AM PDT